This invention relates to an assembly wherein a plurality of resilient monofilaments are attached to a rotary member such that free portions of the resilient monofilaments extend substantially vertically when the rotary member is at rest and such that upon rotation of the rotary member at a predetermined speed, the free portions sever vegetation, such severance serving purposes of mulching and/or cutting and trimming.
A number of new metal blades for mulching lawn mowers have been introduced in recent years having special baffles and deck plugs; however, there has been no proposal for mulching grass using a rotary member provided with a plurality of cutting lines.
Various devices exist in the art for trimming grass with flexible cords secured to a rotary head; for example, U.S. Pat. No. 4,062,114 to Luick teaches use of a flexible cord to cut grass in both a trimmer and an edger, and U.S. Pat. No. 5,197,264 to Lacey discloses a trimmer cutting head having holes of different sizes wherein a filament passes therethrough in a double loop. However, the outward orientation of such a filament makes it difficult to install on the rotary cutting head or to replace it thereon, and it has been found that filaments oriented outwardly have a tendency to break. Moreover, there is no disclosure of a specific size for the holes through which the monofilaments are threaded.
It has additionally been known to incorporate flexible cords or tines into a rotor of a lawn mower. U.S. Pat. Nos. 4,905,465 and 4,909,024 to Jones et al. disclose a rotary cutting member having a plurality of tines formed by flexible cutting filaments passing in a single loop through the rotary cutting member and extending radially outwardly therefrom. Despite the single-loop attachment, the problems of installation difficulty and filament breakage persist due to the outward orientation of the filaments. U.S. Pat. No. 4,936,884 to Campbell teaches a grass cutting device designed to replace a standard lawn mower blade, generally comprising an elongated, downwardly-curved thermoplastic member to which a plurality of flexible tines are attached at either end. These grass-cutting tines extend outwardly and downwardly from the thermoplastic member. Such orientation, however, is likely to cause an overly-deep cut in the turf and thereby gouge it.
In addition to the above-noted shortcomings of prior art devices, there is no teaching of a rotary filament assembly in which resilient monofilaments are attached to a rotary member such that free portions of the resilient monofilaments extend substantially vertically when the rotary member to which they are attached is at rest. Moreover, there is no teaching of using resilient monofilaments to mulch grass in a lawn mower.
It is desirable to cut grass into finer pieces for mulch than those formed by conventional blades of mulching lawn mowers, and there is a need in the art to provide environmentally-conscious owners of standard lawn mowers with an inexpensive means for mulching their cut grass instead of bagging it for eventual dumping in a landfill. Furthermore, there is also a need for an apparatus that can effectively mulch fallen leaves, which can have a higher density than certain grasses, since conventional mulching mowers have had problems reducing leaves into fine mulch particles.